Metal carbide air bearing surface layer on a silicon read/write head element

ABSTRACT

Embodiments include a slider having a silicon body and at least one carbide pad structure embedded therein. At least one head structure for reading and/or writing data is located on the silicon body. The silicon body includes an air bearing surface on which the head is located. The air bearing surface also includes at least a portion of the carbide pad structure thereon. In one aspect, the metal carbide structure may be made from a material such as titanium carbide, zirconium carbide, vanadium carbide, tungsten carbide, or molybdenum carbide. In another aspect, the head may be located on the air bearing surface between carbide pad structures.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to disk drivesystems and to read/write elements and slider devices within thesystems.

DESCRIPTION OF RELATED ART

Magnetic storage systems typically include a rotatable magnetic diskhaving concentric data tracks defined for storing data, and a magneticrecording head or transducer for reading data from and writing data tothe various data tracks. In typical disk drive systems, a stack of oneor more magnetic disks is mounted over a spindle on a drive motor. Thesystem also includes a head actuator for moving the magnetic recordinghead relative to the disk surfaces, and electronic circuitry forprocessing signals to implement various functions of the disk drive.

The head is attached to a carrier or slider having an air bearingsurface which is supported during operation adjacent to the data surfaceof the disk by a cushion of air generated by the rotating disk. Theterms “head” and “slider” are sometimes both used to refer to the sliderhaving a head attached thereon. The slider design affects theefficiency, density, speed and accuracy with which the data can be readand written to the disk. Recording density generally depends on theseparation distance between the recording element of the head and thedisk. As a result, lower flying heights are usually desired to achievehigh areal density recording. Lower flying heights, however, can lead toundesirable interactions between the head and the disk.

As the disk generally includes a hard carbon coating, the slider istypically fabricated from a hard ceramic material so that anyinteractions between the disk and air bearing surface of the slider willnot result in premature wear or breakage of the slider. In addition, theslider material should be relatively inert so that no chemical reactionstake place on the air bearing surface. As illustrated in FIG. 1, slidersare usually derived from a wafer 100 made from a ceramic material suchas a mixture of aluminun oxide (Al₂O₃) and titanium carbide (TiC). Thecomponents of each read/write device are formed or deposited on asurface 12 of the wafer 10 and the wafer 10 is diced into rows such asrow 20 illustrated in FIG. 2. The row 20 has an end surface 12 havingthe read/write device and a row face that is processed, usually bypolishing and/or etching, to form an air bearing surface 22. The row 20is then diced into individual sliders 30 having an air bearing surface22 and a read/write device surface 12 on which the read/write device ispreferably located at a central position 32, as illustrated in FIG. 3.

Fabricating a slider from silicon presents problems because silicon isrelatively soft when compared with slider materials such as Al₂O₃/TiC.This can lead to durability problems. In addition, silicon displaysundesirable start/stop behavior on a disk when compared with othermaterials.

SUMMARY

Preferred embodiments of the present invention relate to disk drivesystems and components therein, including sliders and read/writeelements thereon.

One embodiment includes a slider structure including a silicon bodyhaving an air bearing surface. The air bearing surface includes asilicon surface region and a metal carbide surface region. The metalcarbide surface region is a part of a metal carbide structure embeddedin the silicon body.

Another embodiment includes a slider having a silicon body and at leastone pad structure embedded therein. At least one head structure forreading and/or writing data is located on the silicon body. The siliconbody includes an air bearing surface on which the head is located. Theair bearing surface also includes at least a portion of the padstructure thereon.

Still another embodiment includes a disk drive for reading and writingdisks. The disk drive includes at least one disk and a read/write headassociated with the surface of the disk. The disk drive includes aslider onto which the read/write head is provided. The slider includes asilicon body and an air bearing surface on the silicon body. The airbearing surface includes a silicon surface region and a metal carbidesurface region, with the metal carbide surface including a portion ofthe at least one carbide structure embedded in the silicon body. Thedisk drive also includes an actuator for supporting the slider andpositioning the head across the disk, as well as a rotatable hub formounting the disk.

Embodiments also relate to methods for forming an air bearing surface ona slider. One such embodiment includes providing a silicon slider bodyand forming at least one trench on a portion of one side of the siliconbody. A carbide or nitride structure is formed in the trench. Preferablythe air bearing surface includes both a portion of the silicon body anda portion of the carbide structure. Certain embodiments may also includeforming at least one of a read element and a write element on the airbearing surface after forming the carbide or nitride structure.

In one aspect of certain embodiments, a carbide structure may be formedby a process including filling the trench with a metal carbide andanhydrous metal chloride material and heating the material to produce amelt. The material is then cooled and the chloride material formed fromthe melt is removed. Preferably the remaining carbide material is thenplanarized.

Still another embodiment relates to a method for forming a sliderincluding forming at least one trench into a silicon body and forming anair bearing surface pad structure in the trench that extends to aposition at or above the silicon body. A read/write head is then formedon the silicon body after forming the air bearing surface pad structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described with reference to theaccompanying drawings which, for illustrative purposes, are schematicand not necessarily drawn to scale.

FIG. 1 is a perspective view of a wafer from which a plurality ofsliders may be manufactured.

FIG. 2 is a perspective view of a row cut from the wafer of FIG. 1during slider manufacturing.

FIG. 3 is a perspective view of an individual slider component dicedfrom the row of FIG. 2.

FIGS. 4-8 represent processing steps in the manufacturing of a slideraccording to certain embodiments of the present invention.

FIG. 9 illustrates a top view of an air bearing surface of a slideraccording to an embodiment of the present invention.

FIG. 10 illustrates a side cross-sectional view of the slider of FIG. 8along the line A-A′.

FIG. 11 illustrates a side cross-sectional view of the slider of FIG. 8along the line B-B′.

FIG. 12 illustrates a magnified view of a portion of the sidecross-sectional view of the slider of FIG. 11.

FIG. 13 is a cross-sectional view of a disk drive system according to anembodiment of the present invention.

FIG. 14 illustrates a side cross-sectional schematic view of a slidersuch as that shown in FIG. 10, further showing a read/write elementincluding an AFM tip.

DETAILED DESCRIPTION

Preferred embodiments of the present invention are described withreference to FIGS. 4-13. While the invention is described in terms ofthe best mode for achieving this invention's objectives, it will beappreciated by those skilled in the art that variations may beaccomplished in view of these teachings without deviating from thespirit or scope of the invention.

Formation of silicon based sliders for read/write heads for recordingapplications has not been favored because single crystal silicon has alower hardness and less resistance to chipping than other materials suchas aluminum oxide/titanium carbide. The hardness and resistance tochipping are important in the regime of near contact recording, fordurability purposes. Certain preferred embodiments of the presentinvention relate to processes and structures which may relate to asilicon slider including at least one hard carbide pad embedded in aportion of the silicon slider air bearing surface prior to forming theread/write head element on the air bearing surface of the slider.

Preferred structures provide numerous advantages including the abilityto efficiently produce advanced read/write structures after forming theair bearing surface. This means that the processing steps used forforming the air bearing surface which may, for example, include elevatedtemperatures, will not effect the read/write structure. By forming theread/write head element on the air bearing surface, preferredembodiments also provide the ability to precisely control the height ofthe read/write head elements, which permits the elements to be spacedvery close to the surface of a disk during operation.

Processing steps according to one embodiment of the present inventionare described below with reference to FIGS. 4-8. A silicon wafer orsubstrate 100 may be masked and etched as known in the art to form oneor more trenches or openings 102 in the surface of the substrate 100, asillustrated in FIG. 4. If desired, an optional layer 104 of, forexample, a material including titanium, may be deposited over all or aportion of the silicon substrate 100. The layer 100 may act as anadhesive and/or barrier layer between the silicon and the layer 106 tobe deposited in the openings 102 between the layer 106 and the siliconsubstrate 100. (FIG. 5) A layer 106 including the metal carbideprecursor materials is formed over the silicon substrate 100 and withinthe openings 102.

In one embodiment, an anhydrous metal chloride is used to create thecarbide layer 106 through an interaction with a metal carbide which mayinclude, for example, calcium carbide and/or aluminum carbide. The metalcarbide precursor layer 106 may be deposited using a technique such as,but not limited, to physical vapor deposition (PVD), plasma enhancedchemical vapor deposition (PECVD), or a spray deposition technique. Themetal carbide precursor layer 106 is then heated to a temperaturesufficient to produce a melt (for example, at least 450° C.). Theheating cycle may be very short, for example, in certain embodiments,less than one minute. The heating may take place at atmospheric orvacuum pressure. A short anneal step at higher temperature may also beoptionally included to insure the reaction is complete. The waferincluding the layer 106 is then cooled and the layer 106 includes amaterial including the reacted products of a metal carbide and a metalchloride region. After cooling, the surface may be rinsed with water andmethanol to remove the calcium chloride. In certain embodiments theannealing may be carried out at about 800° C. to about 1000° C. for atime of up to about 48 hours.

After the carbide layer 106 is formed, an etch back and/or polishingstep may be carried out to planarize the carbide as desired. In certainembodiments, the carbide is planned to the same level with the silicon(FIG. 7) and then the non-air bearing surface pad areas etched to apredetermined depth so that the carbide layer regions 106 remaining areraised above the level of the silicon 100, as illustrated in FIG. 8.These raised carbide layer regions 106 may serve as the rails of the airbearing surface of the slider during operation. The desired read/writestructure is preferably formed in or on the silicon substrate 100between the raised carbide layer regions 106. In alternativeembodiments, the carbide layer regions may be processed to be at anydesired level. Processing methods by which the carbide layer height canbe controlled include, for example, polishing, etching, and ion milling.

FIGS. 9-12 and 14 illustrate several views of a slider 200 according tocertain embodiments of the present invention having a plurality ofcarbide structures such as pads 202 embedded in the silicon substrate201. The pads 202 may in certain embodiments be formed from a processsuch as that described above in conjunction with FIGS. 4-8 or may beformed by other processes such as, but not limited to a physical vapordeposition or chemical vapor deposition (CVD) method that does notrequire a melt step as described above.

FIG. 9 is a top view of the air bearing surface 206 of the slider 200showing the relative locations of a plurality of carbide pads 202, aread/write device 208 and electrical wire connects 210. FIG. 10 is aside cross-sectional view of the slider 200 along the line A-A′. FIG. 11is a side cross-sectional view of the slider 200 along the line B-B′.FIG. 12 is a magnified view of a portion of the slider 200 of FIG. 11.

The slider includes openings or trenches 214 into which the carbide padstructures 202 arc disposed. The air bearing surface 206 may include aplurality of carbide pads 202 that are substantially rectangular inshape when viewed from above the air bearing surface. The carbide pads(and the trenches) may be formed into any desired shape. In addition,the air bearing surface may alternatively include a single pad ifdesired. The size, shape, and number of pads may depend on a variety offactors, including the flight characteristics of the slider and theposition of the read/write device thereon. The terms “read/writedevice,” “read/write head,” “read/write structure” and “head” as usedherein may refer to a structure including, but not limited to one ormore read elements, one or more write elements, or a combination of readand write elements.

FIG. 9 also illustrates the relative locations of the read/write device208 and the electrical wire connects 210 according to one preferredembodiment. The read/write device is preferably formed on the siliconair bearing surface 206 between carbide pads 202 at a position equal toor below the height of the carbide pads 202. Electrical connections tothe read/write device may be made by forming trenches or grooves 216into which the electrical wire interconnects 210 are formed The dashedline area 224 in FIG. 12 illustrates a portion of a trench 216 throughwhich the interconnect 210 extends to contact the read/write device 208.The interconnect region 210 illustrated in FIGS. 9-11 may be made up ofa conducting layer 222 and an insulating layer 220 separating theconducting layer from the silicon slider material. The trench 216 may beformed by masking and etching the substrate 201 and may in certainembodiments be lined with an electrically insulating material 220 suchas, for example, SiO₂, followed by a conducting layer 222. Theconducting layer 222 may be formed from a variety of materials such as,for example, aluminum, copper, or alloys including aluminum and/orcopper. If the conducting layer 222 overfills the trench 216, a methodsuch as a masking and etching operation may be used to remove theoverfilled material. This may be necessary because a damascene polishingstep would be difficult to perform due to the carbide pads 202, which,as illustrated in FIGS. 10-12, are preferably raised above the siliconsubstrate 201 surface. Alternatively the electrical interconnects 210may be made on or above the surface of the substrate 201. The electricalinterconnects 210 may preferably extend to an end of the air be surface206 as illustrated in FIG. 9.

Certain preferred embodiments include two sets of trenches, such as, forexample, the trenches 214 and 216. The trenches may be formed at thesame time if desired. One set of trenches 214 may include an adhesion orbarrier layer therein between the silicon and the carbide pad 202. Theother set of trenches 216 may include an insulating layer 220 betweenthe silicon and the conductive layer 222. Any overfill of material fromthe trenches may be removed simultaneously if desired, using a methodsuch as polishing. Once the air bearing surface pads are planarized, thenon-air bearing surface pad areas may be etched or milled down below theair bearing surface. Further processing may then proceed on the recessedsilicon surface.

If desired, a coating layer such as a hard carbon or a polymer may bedeposited over at least a portion of the air bearing surface. Such alayer may in certain embodiments be deposited near the edges 205 of theair bearing surface to protect the slider from damage.

Embodiments of the present invention provide numerous advantages overother slider structures. Typically, the read/write structure is formedfirst and then the air bearing surface is formed. The air bearingsurface formation may include steps such as depositing a layer over theair bearing surface and etching and/or polishing the air bearingsurface. These steps may use elevated temperatures and/or chemicalswhich can harm the read/write head structure. By forming the air bearingsurface first and then forming the read/write structure, as in certainpreferred embodiments of the present invention, the air bearing surfaceprocessing steps will not affect the read/write structure.

In addition, forming the slider from silicon permits a variety ofread/write device structures and circuitry to be formed directly on orin the slider material, thus simplifying the process. For example, asseen in FIG. 14, advanced read/write structures 208 such as those havingan AFM (atomic force microscopy) tip 260, or other fine, fragilestructures can be formed on the air bearing surface 206 without risk ofa later processing step that requires processing conditions that mightdegrade the read/write device structure 208. A wide variety ofread/write structures may be used in embodiments of the presentinvention. Other types read/write structures which may be utilizedinclude, but are not limited to magnetic tunnel junction structures,thin film structures, magneto-restrictive (MR) structures, and giantmagneto-resistive (GMR) structures.

Furthermore, the carbide pads and read/write structure can be formed tominimize the distance of the read/write structure from the disk duringoperation. In certain preferred embodiments the read/write structure isformed on the air bearing surface, which permits it to be located at aheight so that it can be brought very close to the disk surface duringoperation. This is important because to achieve high resolution, theread/write structure should generally be very close to the disk. Massproducing a read/write structure, in which the structure is very closeto the disk, is difficult using conventional read/write head and slideredge type configurations due to difficulties in dicing and handling theindividual sliders precisely. By forming the read/write structure on theair bearing surface according to certain preferred embodiments of thepresent invention, a lower level of dicing precision is necessary, thusenabling a higher production yield.

As illustrated in FIGS. 9-11, the read/write structure may be formedbetween the carbide pads on the air bearing surface. Alternatively theread/write structure may be located at another location on the slidersuch as, for example, the trailing edge.

In another aspect of embodiments of the present invention, a variety ofmaterials may be used as pad structures within the air bearing surfaceof a slider. Some preferred materials include metal carbides such astitanium carbide, zirconium carbide, vanadium carbide, tungsten carbideand molybdenum carbide. More specifically, these carbides may includeTiC, ZrC, V₈C₇, WC, and Mo₂C. Other carbides may also be used,preferably other than silicon carbide (SiC) and those having a hardnessgreater than tat of SiC. Certain embodiments may also utilize othermaterials such as nitrides, for example, aluminum nitride (AIN) as a padmaterial.

FIG. 13 illustrates portions of a disk drive system 300 according toanother embodiment of the present invention The system includes one ormore disks 302 stacked above one another. The disks 302 are capable ofstoring data in concentric tracks. Both sides of the disks 302 may beavailable for storage, and the stack may include any number of suchdisks 302. The disks 302 are mounted to a spindle 304. The spindle 304is attached to a spindle motor, which rotates the spindle 304 and thedisks 302 to provide read/write access to the various portions of theconcentric tracks on the disks 302.

The disk drive system 300 may also include an actuator assembly 306including voice coil motor assembly 308, which controls a head armassembly which may include a positioner arm 310 and a suspensionassembly 312. The suspension assembly 312 includes a slider 200 at itsdistal end. The slider 200 may be similar to the slider 200 describedabove and illustrated in FIGS. 9-12. Other slider structures could alsobe used if desired. Although only one slider 200 is shown, it will berecognized that the disk drive assembly 300 may include one or moresliders for each side of each disk 302 included in the drive. Thepositioner arm 310 may also include a pivot 314 around which thepositioner arm 310 moves. A flexible printed circuit member 316 maycarry digital signals between a chip 318 and the actuator assembly 306.One or more electrical conductors 320 are routed along the positionerarm 310 and suspension 312 to carry electrical signals to and from theread/write device and slider 200. The electrical conductors may befabricated from a conductive material such as, for example, copper,aluminum, or alloys of these or other materials.

It will, of course, be understood that modifications of the presentinvention, in its various aspects, will be apparent to those skilled inthe art. Other embodiments are possible, their specific featuresdepending upon the particular application. For example, the preferredslider body material is single crystal silicon, although polycrystallinesilicon or other materials could also be used. Furthermore, a variety ofdisk drive configurations, geometries, and components may be may beemployed in disk drive systems in addition to those discussed above.

What is claimed:
 1. A slider comprising: a silicon body; an air bearingsurface on the silicon body, the air bearing surface including a siliconregion and a metal carbide region, the metal carbide region comprising aportion of at least one metal carbide structure embedded in the sliderbody.
 2. A slider as in claim 1, wherein the metal carbide regionextends a distance outward from the silicon region.
 3. A slider as inclaim 1, further comprising at least one of a read device and a writedevice on the air bearing surface.
 4. A slider as in claim 3, whereinthe at least one of a read device and a write device is formed on thesilicon region.
 5. A slider as in claim 4, wherein the at least one of aread device and a write device comprises an atomic force microscopystructure.
 6. A slider as in claim 4, wherein the at least one of a readdevice and a write device is formed to be at the same height as the atleast one metal carbide structure on the air bearing surface.
 7. Aslider as in claim 1, further comprising a carbon layer on a portion ofthe air bearing surface.
 8. A slider as in claim 1, wherein the at leastone metal carbide structure includes a plurality of metal carbide padsextending outward from the silicon body, wherein the at least one of aread device and a write device is positioned between two of the metalcarbide pads extending outward from the silicon body.
 9. A slider as inclaim 1, wherein the metal carbide structure comprises at least onecarbide selected from the group consisting of titanium carbide,zirconium carbide, vanadium carbide, tungsten carbide, and molybdenumcarbide.
 10. A slider as in claim 1, wherein the metal carbide structurecomprises a material having a hardness that is greater than that ofsilicon carbide.
 11. A slider as in claim 1, wherein at least one of aread device and a write device is formed on a trailing surface of theslider adjacent to the air bearing surface.
 12. A slider as in claim 1,wherein the metal carbide structure embedded in the slider bodycomprises a metal carbide pad extending to a position level with orabove the silicon surface region on the air bearing surface.
 13. Aslider comprising: a silicon body; at least one structure embedded inthe silicon body; at least one of a read head and a write head disposedon the silicon body; and an air bearing surface on the silicon body,wherein at least a portion of the structure and the at least one of aread head and a write head are provided on the air bearing surface. 14.A slider as in claim 13, wherein the structure comprises a carbidematerial other than silicon carbide.
 15. A slider as in claim 13,wherein the structure comprises a nitride material.
 16. A slider as inclaim 13, wherein the air bearing surface includes a silicon surfaceregion and a carbide surface region.
 17. A slider as in claim 13,wherein the air bearing surface includes a silicon surface region and anitride surface region.
 18. A slider as in claim 17, wherein the nitridesurface region comprises a metal nitride.
 19. A slider as in claim 17,wherein the nitride surface region comprises aluminum nitride.
 20. Adisk drive for reading and writing disks comprising: at least one disk;a read/write head associated with the surface of the disk; a slider ontowhich the read/write head is provided, the slider comprising a siliconbody and an air bearing surface on the silicon body, the air bearingsurface including a silicon surface region and a metal carbide surfaceregion, the metal carbide surface region comprising a portion of atleast one carbide structure embedded in the silicon body; an actuatorfor supporting the slider and positioning the head across the disk; anda rotatable hub for mounting the disk.
 21. A slider as in claim 20,wherein at least one carbide structure embedded in the silicon bodyprotrudes outward from the silicon body.
 22. A slider comprising: asilicon body; an opening extending a distance into the silicon body; anda carbide region within the opening.
 23. A slider as in claim 22,wherein the carbide region includes an exposed portion.
 24. A slider asin claim 22, wherein the slider includes an air bearing surfacecomprising a silicon region and the exposed portion of the carbideregion.
 25. A slider as in claim 24, further comprising a carbon layeron part of the air bearing surface.
 26. A slider as in claim 22, whereinthe carbide region comprises at least one carbide selected from thegroup consisting of titanium carbide, zirconium carbide, vanadiumcarbide, tungsten carbide, and molybdenum carbide.
 27. A slider as inclaim 22, wherein the carbide region extends outward from the siliconbody on a surface of the slider.
 28. A slider as in claim 27, furthercomprising at least one of a read device and a write device formed onthe silicon body on the surface of the slider on which the carbideregion extends above the silicon body.
 29. A slider as in claim 27,wherein at least one of a read device and a write device extends outwardfrom the silicon body at a height equal to that of the carbide region onthe surface of the slider.
 30. A slider as in claim 27, wherein thecarbide material comprises a carbide having a hardness greater than thatof silicon carbide.
 31. A slider as in claim 22, wherein the carbideregion extends to a position level with that of the silicon body on asurface of the slider.
 32. A slider comprising: a silicon body; at leastone structure embedded in an opening extending a distance into thesilicon body; a read/write head disposed on the silicon body; and an airbearing surface on the silicon body, wherein at least a portion of thestructure and the at least one of a read head and a write head areprovided on the air bearing surface.
 33. A slider as in claim 32,wherein the structure comprises a metal carbide material.
 34. A slideras in claim 32, wherein the structure comprises a nitride material. 35.A slider as in claim 32, wherein the carbide material consistsessentially of a carbide having a hardness greater than that of siliconcarbide.
 36. A slider as in claim 32, wherein at least one structureembedded in the opening extending a distance into the silicon bodyprotrudes outward from the silicon body.
 37. A disk drive for readingand writing disks comprising: at least one disk; a read/write headassociated with a surface of the disk; a slider onto which theread/write head is provided, the slider comprising a silicon body and anair bearing surface on the silicon body, the air bearing surfacedefining at least one opening extending therein, wherein a carbidematerial is disposed in the opening and embedded in the silicon body;and a body for supporting the slider and positioning the head across thesurface of the disk.
 38. A disk drive as in claim 37, wherein thecarbide material comprises a carbide having a hardness greater than thatof silicon carbide.